Inkjet image forming apparatuses are widely used in offices, and the style has become increasingly diverse. FIG. 1 illustrates the internal structure of an inkjet printer. As shown in the figure, an ink cartridge 1 is interposed into a mounting portion 200 and fixed on the mounting portion 200 through a locking fastener 105; a cavity 101 is formed by the enclosure of an ink cartridge housing 103; ink in the cavity 101 is supplied to an ink inlet 202 through an ink outlet 102 on the bottom side of the ink cartridge and conveyed to a print head 203; the ink is sprayed on a paper medium by the print head to form text and images; the ink cartridge of the printer is generally arranged on a movable carriage; and an ink cartridge chip 100 is obliquely arranged at a junction of a front side and a bottom side of the ink cartridge 1 and electrically connected with a contact part 220 of the mounting portion. As the ink cartridge chip 100 is arranged at the junction of the front side face and the bottom side face, the light emitted by a light-emitting portion 110 of the ink cartridge chip is blocked by a mounting handle 106 and the mounting portion of the ink cartridge and is hard to be seen by an eye 2 of a user and sensed by a light receiver of the printer, arranged on the front of the front side face and adjacent to the upper side face (not illustrated in the figure). Therefore, a light guide 104 is disposed on the front side face and used for guiding the light emitted by the light-emitting portion 110 on the ink cartridge chip 100 to the upper side face of the ink cartridge, so as to be seen by the user and sensed by the light receiver. FIGS. 2a and 2b illustrate the external structure of the ink cartridge chip 100. As shown in the figure, the ink cartridge chip 100 further comprises an integrated circuit 130 and a plurality of electric contacts 120 electrically connected with the printer, wherein a control unit and a storage unit are usually arranged inside the integrated circuit 130.
The inkjet printer may be provided with a plurality of ink cartridges for the convenience of long-term use or may have different colors. In order to ensure the correct mounting positions of various ink cartridges, the ink cartridge position detection technology is provided.
The ink cartridge position detection may be based on light emitting and receiving. In the prior art, in general, a light source is disposed on an ink cartridge and a light receiver is arranged inside a main body of an image forming apparatus. During the detection of the position of an ink cartridge, the ink cartridge is driven to the position which is directly opposite to the light receiver; the light source of the ink cartridge is controlled to emit light; and the light receiver receives the light and detects and records the luminous quantity. Subsequently, an adjacent ink cartridge is controlled to emit light, and the light receiver receives the light and detects and records the luminous quantity. As the receiver is directly opposite to the ink cartridge to be detected, the luminous quantity of the light received from the ink cartridge to be detected is more than that of the adjacent ink cartridge and may be more than a predetermined threshold value. Therefore, the main body of the image forming apparatus can identify that the position of the ink cartridge is correct, and the detection method of other ink cartridges is the same.
However, the ink cartridge position detection method has the defects that: in the actual manufacturing process, the manufacturing deviation tends to occur inevitably, namely the luminous quantity of the light sources on various ink cartridges cannot be strictly kept equal, the luminous quantity of the adjacent ink cartridge may be equal to or more than the luminous quantity of the ink cartridge to be detected, and thus the conclusion that the position of the ink cartridge is not correct can be obtained, and consequently the rate of false alarm of the image forming apparatus can be increased.